Wireless telegraphy.



No. 684,467. Patented 0st. [5, I901. H. SHOEMAKER.

WIRELESS TELEGBAPHY.

(Application filedleb. 12, 1901.),

(No Model.)

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PATENT HARRY SIIOEMAKER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO MARIE V. GEHRING, OF SAME PLACE.

WIRELESS TELEGRAPHY.

SPECIFICATION forming part of Letters Patent N 0. 684,467, dated October 15, 1901-.

Application filed February 12, 1901- Serial No. 46,987. (No modeld To all whom, it 71mg concern:

Be it known that I, HARRY SHOEMAKER, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Wireless Telegraphy, of which the following is a specification.

My invention relates to improvements in wireless telegraphy, and has special reference to an electrical-wave detector or anticoherer, which restores itself and needs no restoring device and which is so constructed as to cause the resistance of the local circuit to be increased by the action of the wave, thereby making the device very sensitive.

Another object of my invention is the provision of a wireless-telegraph system which employs a magnetic circuit controlled by a transmitting-key to operate the transmitting apparatus, and thus relieve the operator from a great strain were the key connected directly to the apparatus, as is usual.

To attain the desired objects, the invention consists of a wireless-telegraph system embodying novel features of construction and arrangement of parts, substantially as disclosed herein.

In the drawings, Figure 1 is a diagrammatic view of the entire system. Fig. 2 is alongitudinal central sectional view of the electricwave detector or anticoherer, and Fig. 3 is a plan View of the metal-foil wrapper of the inner tube thereof.

Referring to the drawings, A designates the air-plate,which is mounted upon the telescoping standard A so that it can be adjusted to tune the apparatus, and G the ground of the transmitting apparatus, which consists of the Linduction-coil B, having a vibrator B and being in circuit with the battery 0, the stationary point E, and the pivoted lever F. The condenser D is in shunt with said circuit. Adapted to operate this lever is the electromagnet H, connected in circuit with the batteries J and the transmitting-key K, said key being adapted to close the circuit to operate said e1ectromagnet-,and consequently the remainder of the transmitting apparatus. The transmitting-key K and battery J and electromagnct II are all for the purpose of controlling the circuit by operating the lever F, which is the magnetic key. When a circuit is made by the transmitting-key, the electromagnet H is magnetized, and it attracts the magnetic key F, which closes the transmitting-circuit and causes an impulse to be sent. The object of employing a magnetic key is to insure the very best break possible in the primary without making the work of operating the transmitting-key laborious,said magnetic key being provided with a very stiff spring to hold it normally open.

The receiving apparatus consists of the airplates A, supported upon the adjustable telescoping standard A which is raised so as to be in parallel with the standard A and the ground G, each of said plates being connected to the longitudinal stripsL ofthe metal foil sheet M, surrounding the glass tube N, which is suspended in the large tube 0. This sheet of foil is provided with the transverse parallel slit piece P and has extension ends Q, which surround and are soldered to the platinum wires R and S, which pass through the ends of the tube 0. Upon either side of the strips L are the slots L, which pro- Vide the connecting flaps or pieces L, which are broader than the strip L and to which are connected the air and ground wires T and U. This tube 0 is filled with moist or saturated material Tcotton, for instancewhieh absorbent keeps the foil moist or wet, the large tubebeing sealed to prevent evaporation. The strips L are broader in their centers,as at L,so that the resistance of the slots L is increased. By this construction the battery-current is not allowed to flow directly through the slot L. This construction does not afiect the action of the waves; but it these slots L were merely knife slits or cuts the slits P would not accomplish the desired results, as the greater part of the battery-current would be forced through the slits P at the ends and then around through the strip to the wires R and S. By this construction I dispense with choking-coils, as the air and ground plates are connected to the strips L at their centers, and the waves are not carried into the wires R and S until the choking effect is accomplished.

Connected in circuit with the wires R and S are the batteriesVand electromagnets W, which operate the sounder X through the sounder-wire.

It will be seen that by constructing the electric-wave detector or anticoherer of the outside tube filled with absorbent material having suspended therein, by means of the platinum Wires, a central tube covered with metal foil, with air and ground strips and transverse slits around the circumference, I produce a verysensitive form of electric-wave detector or anticoherer which restores itself and needs no restoring device and that choking-coils are dispensed with also.

I have found by experience thatten slits or gaps may be employed to increase resistance more effectively, and thereby produce a very sensitive form of detector. I will give an example of the increasing of the resistance by employing this form of detector. With one slit the resistance is fifty ohms, and when a wave is received the resistance is increased to five hundred ohms. For each slit added the resistance is increased fifty ohms. Therefore three slits would have the resistance of one hundred and fifty ohms, being increased by a wave to fifteen hundred ohms. The difference would therefore be fifty to five hundred with one slit or from one hundred and fifty to fifteen hundred with three, making a difference of thirteen hundred and fifty ohms asaresult. Therefore ifthe resultis increased the anticoherer or detector is made more sensitive.

The operation of my improved system is readily understood; but, briefly stated, it is as follows: The wave is sent from the transmitting apparatus and received at the receiving apparatus, and as the relay is always in circuit with the detector a wave increases the resistance of the detector and demagnetizes the relay, which allows a circuit to be made through the sounder.

From this description it is evident I provide a very simple and practical system of wireless telegraphy which will readily and easily transmit and receive the dot and dash of the Morse code, and by having the plates upon the telescoping standards the same can be raised or lowered to tune the instrument, a pneumatic or other device being employed to operate the standards.

induction-coil in the circuit closed by said means; and a receiving apparatus composed of a detector or anticoherer comprising an outside tube, a central tube, a sheet of foil provided with transverse slits and longitudinal slits, and an absorbent surrounding said foil and tube; an electromagnet or relay always in closed circuit with the detector ex cept when a wave is received, and a soundercircuit adapted to be closed when a wave is received to operate the sounder.

3. A detector or anticoherer comprising an outside tube, a central tube suspended therein and surrounded by a conductor-sheet, said conductor-sheet being provided with transverse slits and longitudinal strips, a filling of saturated absorbent material surrounding the central tube and filling the outside tube and wires connected to the eonductor-sheetof said central tube. a

a. A detector or anticoherer comprising a central tube surrounded by an outside tube, a saturated absorbent between the two, a thin sheet metal provided with a series of transverse slits and longitudinal strips surrounding said central tube, air and ground plates connected to the sheet, and conductorwires connected to the ends of the sheet.

5. A detector or anticoherer comprising a central tube suspended in an outside tube, a sheet of conductor material surrounding said central tube, said sheet being provided with two longitudinal strips and a series of transverse parallel slits, a saturated absorbent filling in the outer tube and filling the outer tube, and wires connected to the conductor material of the central tube and to the ends of said material.

6. A detector or anticoherer comprising an outside tube, a saturated absorbent material filling said tube, a central tube surrounded by said material, a covering of thin' metal surrounding said tube, provided with oppositely-arranged longitudinal strips connected to the air and ground wires, and a series of transverse slits and conductor-wires passing through the ends of the outside tube and connected to the ends of the sheets.

7. In an apparatus for communicating electrical signals by means of Hertz oscillations; and a signalinginstrument; the combination in the receiver; of a detector or an anticoherer comprising an outside tube, a central tube, a sheet of conducting material provided with transverse and longitudinal slits surrounding said central tube, and an absorbent surrounding said sheet and tubes; a circuit through the detector; and a receivinginstrument operated by the influence of such oscillations on said detector.

In testimony whereof I affix my signature in presence of two witnesses.

HARRY SHOEMAKER.

Witnesses:

R. LEAMAN, JOSEPH S. HAGAN.

IIO 

